Tuesday, 26 June 2012

Black Holes

Perseus Black Hole

Photograph courtesy NASA/CXC/IoA/A. Fabian et al.

A
view of the central region of the Perseus galaxy cluster, one of the
most massive objects in the universe, shows the effects that a
relatively small but supermassive black hole can have millions of miles
beyond its core. Astronomers studying this photo, taken by the Chandra
X-ray Observatory, determined that sound waves emitted by explosive
venting around the black hole are heating the surrounding area and
inhibiting star growth some 300,000 light-years away. "In relative
terms, it is as if a heat source the size of a fingernail affects the
behavior of a region the size of Earth," said Andrew Fabian of Cambridge
University.

Black Hole Wind

A
composite x-ray/optical image of the active NGC 1068 galaxy reveals an
enormous plume of hot gas emanating from the supermassive black hole at
the galaxy's center. Scientists think the shape and speed of the plume,
which moves at about 1 million miles an hour (1.6 million kilometers an
hour), are caused by the funneling effect of a doughnut-shaped ring of
cooler gas and dust that surrounds the black hole.

Unexpected X-Rays

Photograph courtesy NASA/CXC/OCIW/P. Martini et al.

In
2000, astronomers studying the A2104 galaxy cluster (in blue)
discovered powerful x-rays emanating from several black holes in regions
previously thought too old and devoid of gas to create such radiation.
They had expected to find perhaps one such x-ray source in the area, but
instead found six. The discovery, made using the Chandra X-ray
Observatory, changed many of the assumptions scientists had made about
the life cycles of galaxies and black holes.

Intermediate-Mass Black Hole

Astronomers
think the object shown in this Chandra X-ray Observatory image (in box)
may be an elusive intermediate-mass black hole. Located about 32
million light-years from Earth in the Messier 74 galaxy (M74), this
object emits periodic bursts of x-rays at a rate that suggests it is
much larger than a stellar-mass black hole but significantly smaller
than the supermassive black holes found at the centers of galaxies. Few
such middling black holes have been discovered, and scientists aren't
sure how they form.

X-Ray Jet

Illustration courtesy NASA/CXC/M. Weiss

An
artist's rendering, made using data collected by the orbiting Chandra
X-ray Observatory, shows a quasar galaxy with a jet of high-energy
particles extending more than 100,000 light-years from the supermassive
black hole at its center. The object, located 12 billion light-years
from Earth, is the most distant such jet ever detected. These quasar
jets are formed when electrons emitted from a black hole impact with
cosmic background radiation left by the big bang, giving astronomers
clues about the conditions in the early universe.